Method of and apparatus for agitating



Apnl 19, 1932. J. B. PERKINS METHOD OF AND APPARATUS FUR AGITATING FiledMarch 7, 1929 INVENTOR. 61005 5 Per/tins A TTORNEYS Patented Apr. 19,1932 UNETEE STATES JACOB B. PERKINS, OF CLEVELAND, OHIO METHOD OF ANDAPPARATUS FOR AGITATING Application. filed March 7,

In the agitating or mixing of liquid masses in which there is muchtendency to separation of constituents, considerable difficulty isencountered; and where constituents tending not only to settle out butalso to cake at the bottom of the container are involved, thedifficulties increase, and under such circumstances it has beencustomary to empty the container on any cessation of operations in orderto avoid trouble in restarting. This is inconvenient andinterferes withgood operating schedules. An agitating system capable of efficientoperation without undue power consumption or complicated mechanicalconstruction, and making possible the rapid handling of caked depositsis accordingly highly desirable.

To the accomplishment of the foregoing and related ends, the invention,then, consists of the features hereinafter fully described, andparticularly pointed out in the claims, the following description andthe annexed drawings setting forth in detail certain illustrativeconstruction contemplated in the invention, this being however anexemplification of but one of the various ways in which the principle ofthe invention may be employed.

In said annexed drawings:

Fig. 1 is an axial sectional view of an embodiment of the invention; andFigs. 2 and 3 are sectional'details. Y Y

Referring more particularly to the drawings, there is shown a container1, and an impelling means, advantageously a screw propeller S, carriedby a shaft 3 and driven from any suitable source of power. The containermay be of shape and dimensions required by particular circumstances,ordinarily a cylindrical shape being most desira-t ble.

The impeller is mounted in the lower portion of the container, andpreferably the blades 2 are regulable as to pitch, this being providedby any suitable means, as for instance journalled stems 2a and setscrews 9]) for tightening against the respective bladestems to hold themin desired pitch position.

In relation with the impelling means is a current guide in the form of atubular shell,

1929. Serial No. 344,971.

the cross section of which may be of noncircular form, but whichordinarily is circular. Such current guide is regulable moreover as toits height in the container, whereby I it may be readily adapted tovarious amounts of liquid material under treatment. To such end, theguide is of a telescopic character, being made up of any preferrednumber of sections 4a, 46, it, these sections nesting closely so as tofavor adju'stability without material space requirement. In thedetailshown. the section adjacent the impeller is held in fixed position, asby support rods or standards 5, and the sections 46, thence aretelscopiv cally mounted thereon, the section 40a for instance beingslightly flanged outwardly at its upper end, while the section 46 iscorrespondingly flanged inwardly at its lower end.

and so on. Means for raising and lowering v the sections are provided,for instance cables 6 attached to the upper section, and wound on drums7 operated by shaft 8. The latter may be actuated by a hand wheel 9through suitable gearing. lar guide may be extended to whatever lengthmay be desired in view of the requirements at any given time, and theupper edge of the guide may be maintained at all times at a In thismanner, the tubusuitable distance below the surface of the liquid so as'to allow of circulation. If desired, a tell-tale or indicator 10 may besecured to the cable at a suitable distance above the top of the uppersection of the tubular guide to facilitate maintaining propersubmergence depth, it being then merely necessary to regulate the cableso thatthe indicator 10 is at the surface of the liquid.

It will be observed that the tubular guide divides the liquid massundergoing treatment into two columns, an inner or central column and anouter or peripheral column, the tubular guide making a divisiontherebetween; and accordingly the liquid mass may circulateefi'ectively, as set in motion by the agitating impeller. Moreover, thecross sectional areas within and without the tubular guide arepreferably substantially equal, this being readily attained bydimensioning the tubular guide in accordance with the mathematicalrequirements of the areas of the concentric circle-s. In this manner,the area for circulatory action is equal inside and out with respect tothe tubular guide, and an even circulation is favored. The same equalityof 5 Circulatory area at all points may be furthered also by maintainingthe distance between the lower edge of the tubular guide andthe floor ofthe container, and the distance: between the upper edge of the tubularguide and the surface of the liquid such as to be consistent with thecross sectional circulatory require ments referred to, and thus acirculatory circuit may be had which at all points ofl'ers'substantially equal freedom of flow.

The floor of the container is preferably recurved, as at 12,'the sweepof liquid thus being caused to exert ascouring action upon the bottom;and with absence of eddy currents in dead corner spaces, thedirect forceof the current stream is made available, and consequently depositedmaterials are capable of being readily loosened up and put intocirculation.

In order to check tendencies towards circular swirl of the entire fluidmass in the zone between thecontainer and the tubular guide, baffleplates 13- may be suitable positioned, a convenient mounting involvingfor instance channel forms 14 secured to the container walls, and withabaflie plate correspondingly flanged as at 15, such plate may be sliddown the channel and into place, to project out into the space betweencontainer and tubular guide.

In large size units,.it isdesirable to make adequate provision'formounting andlubrication of the impeller shaft, and as shown in Fig. 1,this may comprise a. stuffing box 16 and a step bearing 17 under thecontainer floor. The bearing box furtliermoremay be provided with oilinlet and outlet pipes'18', 19, the former leading from a suitablesource of oil supply and the latter. to a receiver. In this manner,.anadequate'supply of lubricant to the step bearing may be had under allconditions of usage. I

In operation, if it is desired to start with a small amount ofmaterial,the telescopic guide is collapsed into its lowest position,

the ring sections then nesting closely concentrically at the lower endof the container adjacent the impeller. WVith the starting materialcharged into'the container,.and the-impeller inmotion, the blades maybeset at such pitch as to direct the current flow for example downwardlyagainst the-floor. of the container, the liquidmass is thus churned andagitated, and with the upper edge ofthe guide maintained at a spaceddistance below the surface of the liquid, a circulatorycircuit is had.\Vithan increased amount of liquid under treatment, the tubular guide israised correspondingly, and by gauging its depth of submergenceby'reference to the indicator 10, adjustment being had so as to maintainthe indicator at the surface of the liquid, the height of the guide mayat all times be set to correspond to the amount of liquid to be treated,whether of relatively small amount, or with a container full. As seen,also the churning and agitation proceeds, components which tend tosettle out being set into vigorous motion, effecting progressive andthor' ough intermixture, and the mass circulates as a downwardlydirected column inside of the tubular guide, thence impinging with ascouring action on the floor 12 and thence up in the-space between thecontainer wall and the tubular guide, and over the top of the latter tothe impeller. At the same time, the bafiling action-of the plates 13checks circular swirling. One or more arms-11 may be arranged betweenthetubular section to and the container, a convenient form being anextension of the arm of'the spider 4 to en'- gage for instance by aforked end over the platel3.

Instead. of setting the impeller blades to drive the materialdownwardly, the pitch may be reversed if desired so as to drive thecentralicolumnupwardly, the material thence flowing downwardly betweenthe tubular guide and the container wall and sweeping over'the bottomreenters past the impellers.

Mixtures which ordinarily are difiiculty kept. in suspension, asforinstance cement slurries, pulp mixtures, paint mixtures, etc, are thnsreadily handled,and by reason of the effective scouring action exertedat the hottomof the container, operations may be suspended if required,and on-restarting,. material caked at thebottom may be secured loose andput into uniform admixture. By reasonfurther of the regulable characterof the tubular guide, as seen, compositions which include diflicultlymiscible components and easily miscible components may be readilyhandled, the difiicultly miscible components being put in first, andthese being brought to a desired. homogeneity, the tubular guide beingset for such volume, and'with progressive addition of the otherconstituents, the tubular guide being regulated correspondingly,.theentire mass may. be brought to final homogeneity. Where desired alsocontinuous-type operation may be as readily'had, the components beingcorrespondingly supplied, and draw off at a bottom outlet beingcontrolled propori ionately.

Other modes-of applying the principle of the invention may be employed,change being made as regards the details described, provided the stepsor means stated inany of the following claims, or the equivalent ofsuch, be employed.

I therefore particularly point out and distinctly claimas my invention il. A method of agitating liquids, which comprises churning the liquidwhile moving it in central and peripheral columns in circuit, andirrespective of the amount of liquid maintaining the separation betweencentral and peripheral portions at substantially con stant distancesbelow the surface of the liquid and above the floor of the container forsuch liquid.

2. A method of agitating liquids, which comprises churning the materialwhile moving it in a central column and a sharply separated peripheralzone with a recurved sweep between, the cross sectional area of thecentral column and the peripheral zone being substantially equal, andmaintaining the separation between central and peripheral portions atsubstantially constant distances below the surface of the liquid andabove the floor of the container for such liquid.

3. In apparatus of the character described, the combination of acontainer having a recurved floor, an impeller above such floor topropel fluid in the container, and means for equalizing circulation ofthe propelled fluid, said means including a tubular guide spaced withinthe container to provide a cross-sectional area within the guidesubstantially the same as that between the guide and the container.

4. In apparatus of the character described, the combination of animpeller of regulable pitch, a tubular guide, and a container having afloor adjacent the propeller presenting a recurved surface.

5. In apparatus of the character described, the combination of acontainer, an impeller, a tubular guide, vertical baflies, and means onthe container walls to removably hold said baflies.

6. In apparatus of the character described, the combination of acontainer, an impeller, channel-form supports on the inner wall of saidcontainer. and b'aflle plates having flanges adapted to slide into suchchannels.

7 In apparatus of the character described, the combination of acontainer, an impeller at the lower portion thereof, said containerhaving a recurved floor, a tubular guide of a proportion affording across sectional area therewithin substantially equal to the crosssectional area between the guide and the container, said guide beingsupported from the floor of the container at a distance affordingsubstantially the same circulatory section as between the guide and thecontainer wall, and means for maintaining the upper and lower edges ofthe guide respectively at uniform distances below the surface of theliquid undergoing treatment and above the bottom of such container.

8. In apparatus of the character described, the combination of acontainer an impeller at the lower portion thereof, a guide comprising atubular section fixed adjacent the propeller and telescopic sectionsmovable on said fixed section, means for regulating the depth ofsubmergence of the top of such sections, and

means for checking rotational swirl between said guide and the containerwalls.

9. In apparatus of the character described, the combination of acontainer having a recurved floor, an impeller adjacent thereto, a

JACOB B. PERKINS.

